Tuneup for 1992 Merc Benz 300E ? on 1992 Mercedes-Benz 300E

How often should I get tuneup for car I have had at 250,00 miles?

The owner's manual should tell you how often, are you having issues? When did you last have one done?
Sir, if I had an owner's manual, do you think I would be asking this question about how often a tune up?